The invention relates to an apparatus and a method for programming at least one control device for a motor vehicle.
German Patent Document DE 36 24 456 discloses an electronic system for a motor vehicle having a plurality of local electronic controls for various vehicle systems. The local controls which are associated with several systems, and contain correspondingly different program steps and fixed variables, are connected to a central control unit which actuates them when the motor vehicle is started up, and/or at regular intervals, and selects program steps and fixed variables associated with the respective assemblies.
The central control unit, which may be a part of one of the local control devices, can be encoded externally in accordance with the vehicle type. By means of the central control unit, the assignment of a particular local control to the vehicle-specific assembly is thus effected individually, it being possible for the fixed variables and program steps which are identical for several vehicle types to remain unaffected. Thus, such fixed variables and program steps can be provided in resident form in corresponding control devices to a certain extent as frame firmware.
German Patent Document DE 41 28 922 A1 describes, inter alia, a programming arrangement for electronic controls in a vehicle in which the type of vehicle which is, for example, being manufactured and its equipment are detected by means of an identification system, and corresponding vehicle configuration data are prepared and read in from an external programming device into a vehicle control device. The external programming device communicates with a host computer which is also external in order to prepare the programming data for the control device in each case in a vehicle-specific fashion.
The object of the present invention is to provide a method and apparatus for programming at least one motor vehicle control which is to be retrofitted or replaced, which method and apparatus achieve the simplest, most reliable and effective possible programming of such a control device.
This object is achieved according to the invention by a programming arrangement based in a vehicle having a plurality of local control devices which are connected to a central control device, and can communicate with one another (and with the central control device) via a bus system, even before their original programming.
A control program for distributing configuration data via the bus system, and for loading configuration data out of the vehicle configuration memory into the local control devices, is resident in the central control device, and each of the control devices is equipped with a bus function for receiving, selecting and storing vehicle configuration data distributed to it. The vehicle configuration data can be transmitted via the bus system to the individual control devices and stored there, at least by initialization of the control program, which is resident in the central control device.
According to the invention, at least one motor vehicle control device which is to be retrofitted or replaced is supplied with continuous electric power even when the vehicle is stationary however, its memory (which receives vehicle configuration data) is cleared when the control device is removed from the vehicle. Furthermore, such control device contains a separate, resident control program which can detect an electronic "non-programmed" marker (or can detect an empty state of its volatile memory as such a marker) and the control device automatically transfers the vehicle configuration data required by the central control device out of the vehicle configuration memory of the central control device, via the bus, and stores them in a volatile fashion.
In comparison with conventional arrangements for individual selective reprogramming of control devices to be refitted or replaced, this arrangement eliminates the need to maintain additional equipment in garages for configuration or reprogramming of replaced or retrofitted control devices. At the same time, it also dispenses with the problems associated, for example, with highly stressed plug-in contacts between vehicle and such external additional devices.
The method according to the invention permits one or more motor vehicle control device to be programmed in a motor vehicle which contains a plurality of such control devices connected to communicate with one another via a bus. One of the control devices which has a central function is equipped with a non-volatile vehicle configuration memory in which information relating to the type of the vehicle, its equipment and the type and number of control devices which are present in the vehicle, can be stored. According to the invention, such programming is performed in the case of retrofitting or of replacement of one or more of the control devices, by the following steps:
Initialization is performed by comparing data stored in the memory of the retrofitted or replaced device(s) with the vehicle configuration data stored in the configuration memory of the central control device; and
In the case of differences in these data, the data in the newly added or replaced control device are overwritten with current vehicle configuration data called up from the vehicle configuration memory.
During a subsequent replacement or addition of a control device, its initial programming or reprogramming in the vehicle can therefore be performed directly out of the vehicle configuration memory of the central control device, without external support, under the control of the newly installed control device, which is characterized as "not yet programmed."
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.